You know, World War II was fought using the same cheap surplus ammo we all think is now inferior.

Actually, it isn't that simple, of course. At the time, it was new and that makes a big difference. Ammunition keeps fairly well but the older stuff with corrosive primers seems to turn green (around the primer) eventually, even inside a tin can. Most of the standard cartridges used in WWII, including .303, .30-06, 8mm Mauser (7.92mm) and 7.62x54R remained in use for another fifteen years, even longer in some places and of course, the latter is still a standard cartridge in lots of places. Some others, such as 6.5x55, were also used for another 20 years but I doubt if the Japanese cartridges were used anywhere (by an army, that is) after the war.

I once saw a fire started at an indoor range but I have no idea what caused it. It was on the floor at the back of the range.